Per cent low attenuation volume and fractal dimension of low attenuation clusters on CT predict different long-term outcomes in COPD

Shimizu, Kaoruko; Tanabe, Naoya; Tho, Nguyen Van; Suzuki, Masaru; Makita, Hironi; Satô, Susumu; Muro, Shigeo; Mishima, Michiaki; Hirai, Toyohiro; Ogawa, Emiko; Nakano, Yasutaka; Konno, Satoshi; Nishimura, Masaharu

doi:10.1136/thoraxjnl-2019-213525

Cited by 24 publications

(24 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These findings suggest that exacerbations-induced coalescence of emphysematous clusters made pre-existing clusters larger, which supports the disruptive role of mechanical forces described above. Furthermore, these results also prove that D and LAA% do not always change simultaneously, which may explain why LAA% and D have different predictive roles in the long-term prognosis of COPD (Shimizu et al, 2020).…”

Section: Simulation Studiesmentioning

confidence: 52%

“…In addition, D has also revealed relationships between exacerbation and emphysema progression (Tanabe et al, 2011) and between continuous smoking and spatially heterogeneous emphysema progression (Tanabe et al, 2012). Further, Shimizu et al (2020) recently reported that while LAV% predicts lung function decline and 10-year mortality, the exponent D predicts shorter time to exacerbation in patients with COPD. This supports the notion that the power-law exponent D reflects a distinct clinical status that the more standard emphysema index LAV% does not include.…”

Section: Computed Tomographymentioning

confidence: 97%

“…In the last decade, the technical advances in CT imaging and analysis software have made it possible to invoke fractal analysis applied to emphysema and airway disease in large populations and showed potential for FD and D as imaging biomarkers to predict COPD outcomes (Mishima et al, 1999;Coxson et al, 2008;Tanabe et al, 2011Tanabe et al, , 2018aTobino et al, 2017;Hwang et al, 2019;Shimizu et al, 2020). Unfortunately, despite much progress, the power-law and fractal analyses are less commonly used by clinicians and researchers compared to the simple quantitation of emphysema and airway disease.…”

Section: What Are Power Laws and Fractals?mentioning

confidence: 99%

“…Target of the powerlaw and fractal analysis Outcomes Parenchyma Mishima et al, 1999 LAA size distribution Detection of early COPD (exponent D: healthy 1.68, COPD with mild emphysema 1.38) Coxson et al, 2003 LAA size distribution LVRS response (exponent D: 0.56) Gietema et al, 2011 LAA size distribution Association with visual emphysema assessment (exponent D: panacinar emphysema 1.63, CLE 1.99, PSE 2.12) Yuan et al, 2010 LAA size distribution Estimate pathological emphysema (exponent D range: 0.1-2.5) Camp et al, 2009 LAA size distribution Sex difference in emphysema (exponent D: male 1.65, female 1.67) Tanabe et al, 2011 LAA size distribution Exacerbation and emphysema progression (exponent D: exacerbator 1.29, non-exacerbator 1.45) Tanabe et al, 2012 LAA size distribution Spatial pattern of smoking-induced emphysema progression (exponent D: former 1.83, current smokers 1.80) Hwang et al, 2019 LAA size distribution Long-term mortality (exponent D: 0.43) Tanabe et al, 2018a Relatively lower attenuation area size distribution Sensitive detection of emphysema progression in current smoker (exponent D: former 1.25 current smokers 1.30) Tobino et al, 2017 LAA size distribution Differential diagnosis of COPD from other cystic lung diseases (exponent D not shown) Mondoñedo et al, 2019 LAA size distribution Super emphysema cluster emergence in disease progression (exponent D: control 1.63, COPD 1.30) Shimizu et al, 2020 LAA size distribution Future exacerbation (exponent D: 1.50) Airway Bodduluri et al, 2018 Airway tree (boxcounting)…”

Section: Authorsmentioning

confidence: 99%

See 3 more Smart Citations

Fractal Analysis of Lung Structure in Chronic Obstructive Pulmonary Disease

et al. 2020

Self Cite

View full text Add to dashboard Cite

Chest CT is often used for localizing and quantitating pathologies associated with chronic obstructive pulmonary disease (COPD). While simple measurements of areas and volumes of emphysema and airway structure are common, these methods do not capture the structural complexity of the COPD lung. Since the concept of fractals has been successfully applied to evaluate complexity of the lung, this review is aimed at describing the fractal properties of airway disease, emphysema, and vascular abnormalities in COPD. An object forms a fractal if it exhibits the property of self-similarity at different length scales of evaluations. This fractal property is governed by power-law functions characterized by the fractal dimension (FD). Power-laws can also manifest in other statistical descriptors of structure such as the size distribution of emphysema clusters characterized by the power-law exponent D. Although D is not the same as FD of emphysematous clusters, it is a useful index to characterize the spatial pattern of disease progression and predict clinical outcomes in patients with COPD. The FD of the airway tree shape and the D of the size distribution of airway branches have been proposed indexes of structural assessment and clinical predictions. Simulations are also useful to understand the mechanism of disease progression. Therefore, the power-law and fractal analysis of the parenchyma and airways, especially when combined with computer simulations, could lead to a better understanding of the structural alterations during the progression of COPD and help identify subjects at a high risk of severe COPD.

show abstract

Section: Simulation Studiesmentioning

confidence: 52%

Section: Computed Tomographymentioning

confidence: 97%

Section: What Are Power Laws and Fractals?mentioning

confidence: 99%

Section: Authorsmentioning

confidence: 99%

See 2 more Smart Citations

Fractal Analysis of Lung Structure in Chronic Obstructive Pulmonary Disease

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…We thus hypothesized that central airway disease might develop independently of peripheral lung disease in the AD subtype of COPD patients. For this goal, using two cohorts: the Kyoto-Himeji cohort and the Hokkaido COPD cohort [24][25][26], this study specifically aimed to prove that the classical CT-based AD subtype, defined using central airway dimension, would be less severe in the SAD compared with the ED subtype and have some distinct morphological and clinical features.…”

Section: Introductionmentioning

confidence: 99%

Central airway and peripheral lung structures in airway disease-dominant COPD

Tanabe

Shimizu

Terada³

et al. 2021

ERJ Open Res

Self Cite

View full text Add to dashboard Cite

The concept that the small airway is a primary pathological site for all COPD phenotypes has been challenged by recent findings that the disease starts from the central airways in COPD subgroups and that a smaller central airway tree increases COPD risk. This study aimed to examine whether the computed tomography (CT)-based airway disease-dominant (AD) subtype, defined using the central airway dimension, was less associated with small airway dysfunction (SAD) on CT, compared to the emphysema-dominant (ED) subtype.COPD patients were categorised into mild, AD, ED, and mixed groups based on wall area percent (WA%) of the segmental airways and low attenuation volume percent in the Kyoto-Himeji (n=189) and Hokkaido COPD cohorts (n=93). The volume percent of SAD regions (SAD%) was obtained by nonrigidly registering inspiratory and expiratory CT.The AD group had a lower SAD% than the ED group and similar SAD% to the mild group. The AD group had a smaller lumen size of airways proximal to the segmental airways and more frequent asthma history before age 40 years than the ED group. In multivariable analyses, while the AD and ED groups were similarly associated with greater airflow limitation, the ED, but not the AD group, was associated with greater SAD%, whereas the AD, but not the ED group, was associated with a smaller central airway size.The CT-based AD COPD subtype might be associated with a smaller central airway tree and asthma history, but not with peripheral lung pathologies including small airway disease, unlike the ED subtype.

show abstract